Steganography is a subset of cryptography. It specifies the study and science behind creating and deciphering hidden data within otherwise normal-seeming data. For example, someone might insert a line of text onto a strand of hair of a high resolution portrait. The only way to read such text would be to zoom in on that specific location. The sender and recipient probably have a certain understanding that would allow for the veils of obscurity to be felled and the message to be received.
History:
The word is derived from the combination of the Greek words steganos, for “covered,” and graphia, for “writing.” An appropriate story to begin a study of the subject's history is found in the classical historiography of Herodotus. During the Persian expansion under Darius I, city states such as Miletus among others found in Asia Minor came under subjugation. One of these former rulers, Histiaeus, desired to revolt. However, having been taken away on the Persian campaign into Scythia, it would fall to his ally-at-home, Aristagoras to take such action. Histiaeus shaved the head of one of his trusty slaves and tattooed this instruction upon his head. After allowing for his hair to grow back, the slave was sent back to Miletus with the simple instructions to have his head shaved by the authority there. Aristigoras was then able to obtain Hisiaesus's instructions.
Uses/Types:
This manner of communications becomes a most clever way of seeming innocuous while actually being devious. Especially in times of war, steganography can be an incredibly potent weapon of information. Something as simple as taking the second letter of each word in a sentence could be a practical quandary for code breakers who might be used to the complexities of algorithmic cryptography.
On a professional and/or official level, watermarks on physical currency or digital one's on copyrighted media are not at all apparent though they hold important information of ownership. Embedding a line of code into program that is rife with unintelligible computer-speak would be an secure way way send a message, only decipherable by the recipient or perhaps experts who are trained to look for code anomalies. This particular assignment was uncovered by looking for a unique block of text within the HTML code of the first quest hub page on the course blog.
Overview:
Steganography is a subset of cryptography. It specifies the study and science behind creating and deciphering hidden data within otherwise normal-seeming data. For example, someone might insert a line of text onto a strand of hair of a high resolution portrait. The only way to read such text would be to zoom in on that specific location. The sender and recipient probably have a certain understanding that would allow for the veils of obscurity to be felled and the message to be received.
History:
The word is derived from the combination of the Greek words steganos, for “covered,” and graphia, for “writing.” An appropriate story to begin a study of the subject's history is found in the classical historiography of Herodotus. During the Persian expansion under Darius I, city states such as Miletus among others found in Asia Minor came under subjugation. One of these former rulers, Histiaeus, desired to revolt. However, having been taken away on the Persian campaign into Scythia, it would fall to his ally-at-home, Aristagoras to take such action. Histiaeus shaved the head of one of his trusty slaves and tattooed this instruction upon his head. After allowing for his hair to grow back, the slave was sent back to Miletus with the simple instructions to have his head shaved by the authority there. Aristigoras was then able to obtain Hisiaesus's instructions.
Uses/Types:
This manner of communications becomes a most clever way of seeming innocuous while actually being devious. Especially in times of war, steganography can be an incredibly potent weapon of information. Something as simple as taking the second letter of each word in a sentence could be a practical quandary for code breakers who might be used to the complexities of algorithmic cryptography.
On a professional and/or official level, watermarks on physical currency or digital one's on copyrighted media are not at all apparent though they hold important information of ownership. Embedding a line of code into program that is rife with unintelligible computer-speak would be an secure way way send a message, only decipherable by the recipient or perhaps experts who are trained to look for code anomalies. This particular assignment was uncovered by looking for a unique block of text within the HTML code of the first quest hub page on the course blog.
Sources:
1) http://www.sans.org/reading_room/whitepapers/stenganography/steganography-past-present-future_552
2) Herodotus
3) http://dictionary.merriam-webster.com/dictionary/steganography
4) http://www.jjtc.com/Steganography/